the ash usually consists largely of silica,
and this must be worked off by flux. If the ash be carbonate of lime, it
will, in most cases, serve itself usefully as flux. In hearth puddling,
it is important not only that the peat or peat-coal contain little ash,
but especially that the ash be as free as possible from sulphates and
phosphates, which act so deleteriously on the metal. The notion that, in
general, peat and peat charcoal are peculiarly adapted for the iron
manufacture, because they are free from sulphur and phosphorus, is
extremely erroneous. Not infrequently they contain these bodies in such
quantity, as to forbid their use in smelting.

In the gas-puddling furnace, or in the ordinary reverberatory, impure
peat may, however, be employed, since the ashes do not come in contact
with the metal. The only disadvantage in the use of peat in these
furnaces is, that the grates require cleaning more frequently, which
interrupts the fire, and, according to Tunner, increases the consumption
of fuel 8 to 10 _per cent._, and diminishes the amount of metal that can
be turned out in a given time by the same quantity.

Notwithstanding the interruption of work, it has been found, at
Rothburga, in Austria, that by substitution of machine-made and
kiln-dried peat for wood in the gas-puddling furnace, a saving of 50
_per cent._ in the cost of bar iron was effected, in 1860. What is to
the point, in estimating the economy of peat, is the fact that while 6.2
cubic feet of dry fir-wood were required to produce 100 lbs. of crude
bar, this quantity of iron could be puddled with 4.3 cubic feet of peat.

In the gas furnace, a second blast of air is thrown into the flame,
effecting its complete combustion; Dellvik asserts, that at Lesjoeforss,
in Sweden, 100 lbs. of kiln-dried peat are equal to 197 lbs. of
kiln-dried wood in heavy forging. In an ordinary fire, the peat would be
less effective from the escape of unburned carbon in the smoke.

In other metallurgical and manufacturing operations where flame is
required, as well as in those which are not inconvenienced by the
ingredients of its ash, it is obvious that peat can be employed when
circumstances conspire to render its use economical.

17.--_Peat as a source of illuminating gas._

Prof Pettenkofer, of Munich, was the first to succeed in making
illuminating gas from wood; and peat, when operated according to his
method, furnishes also a gas of good quality, though somewhat i